During adverse conditions, such as drought, snails have the ability to sleep for long periods of time. Perhaps the better description is that they estivate (the summer equivalent to winter hibernation).
The Cambridge Natural History 1895Â compendium cites an incident involving the ‘sleeping’ of snails. Whilst travelling in Egypt a Mr. Vernedi discovered a bush covered with snails. He plucked a few and decided to keep them in his desk drawer. Â Somehow, four years later, two of them ended up in the British museum, alive and kicking (or should I say ‘alive’ and ‘slipping’).